Audio signal modulating system with pre-emphasis

Claim 1

An audio signal modulating system for an audio system having an FM tuner, a recording medium reproducing device, and stereo modulator means for modulating an audio signal from the recording medium reproducing device to produce a composite signal to be received by the FM tuner for reproducing the audio signal, the modulating system further comprising: control means for automatically controlling a level of the audio signal applied to the stereo modulator means to a level which prevents tone quality of sound reproduced by the FM tuner from deteriorating, wherein the control means includes a pre-emphasis circuit for emphasizing high frequencies of the audio signal, the pre-emphasis circuit includes a) an ordinary pre-emphasis circuit to raise an input audio signal in a high frequency range to a first level, and b) a raised pre-emphasis circuit to raise the input audio signal to a second level which is higher than said first level.